How to build world-class studios


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Studio wiring

How many engineers have seen neat and well-documented wiring in new studios? Probably a fair number. How many have seen neat wiring in five-year-old studios? Not many engineers have, because it is almost impossible to build studios, no matter how neat and well-documented, that retain the same level of organization and coherence after several years in the real world of last-minute remotes, unexpected equipment failures and format changes made without notice to the engineering department. It seems almost impossible to stay ahead of the game, but it's not.



Allow enough space in the rack to provide for any future expansion, whether it is adding another station to the facility or accommodating a new format. Clear Channel Hartford rack room by Scott Frances and courtesy of the Lawrence Group Architects, St. Louis.

Expansion will happen. I have never seen a studio or studio facility that didn't need to be expanded within a year or so of its construction. Provide plenty of room for expansion by running extra wire and cable pairs, by allotting additional space for equipment and for wiring blocks, and by providing additional capacity in the entire infrastructure.

Pull more pairs than needed from each rack or cabinet to the wiring block area in each studio and from each studio to the rack room. Order cabinets and racks large and deep enough to accommodate new source equipment, new satellite and remote equipment, and especially new computers. Size generators, UPS units and HVAC equipment to handle additional loads. Save space in the building for future studio areas. Size the rack room to accommodate additional racks, but resist the temptation to let the current wiring expand to fill that available space.

Use only smart wires. Don't wire a studio using anything but AES-3 compatible cable. AES-3 requires a twisted-pair cable impedance of 110Ω while traditional analog twisted-pair is typically 30Ω to 40Ω. Analog wire should not be used to carry an AES signal more than a few feet. Even if your current need is for analog audio only, the AES cable does it no harm, and will be in place when and if your station makes the digital transition, which will become more and more likely as digital equipment prices continue to fall and performance and ease of use rises. The good news is that 110Ω cable is quite common and is available in single pair, multiple pair or snake cable and microphone-tough cable in wire sizes as small as 26 gauge. All Ethernet cable (CAT5, CAT5E and CAT6) cable is rated at 100Ω, which is within the AES-3 audio specification. Ethernet cables are available in 4-, 8-, 12- and even 25-pair configurations, which today are cost-effective compared to traditional individually-shielded, twisted-pair cables. CAT5 is available with overall shields too, although balanced, line-level, low-impedance audio does not usually require shielding.

Multiple-pair, twisted-pair, 110Ω ribbon cables rolled in a tough jacket — and even shielded — are also available. These can be quickly and easily mass terminated to connectors or bulk punch-block connections.

Label the wires clearly. My first experience with heat-shrink labels used white pieces of heat shrink mounted on plastic tabs, like cartridges on an ammo belt, that could be loaded into a modified IBM Selectric typewriter. While they were expensive and time-consuming, the level of professionalism they brought to my wiring generated many positive comments. Today there are improved versions of this that are quicker and cheaper.

Personally, I use sheets of self-laminating laser printer labels that will fit on most cables of less than 1" diameter. I have settled on four fields on each label to indicate where each end of the wire goes, what type of wire it is and the color. The first two fields are for troubleshooting, and the last two are so that my crew doesn't put the label on the wrong wire. Color-coding can be a great tool; just be sure that none of your installers is color-blind.



Various methods exist to create neat and practical labels, some of which are quite advanced and offer bar codes to simplify accessing data. Photo by Don Danko, CBRE CBNT.

Whenever possible, use wiring blocks. Traditional telephone-type 66 blocks are easy to find, offer lots of accessories and can be purchased from stock from several telecom and electronics distributors. Keep in mind that CAT5-rated 66 blocks should be used for AES-3 signals. ADC, AVP, Krone and others make excellent, high-density, high-reliability wiring blocks designed for professional and digital audio.

Keep the wiring blocks neat. Allow enough room to mount all the blocks needed for the current installation and include space for several spares. Because shielding is usually not needed for balanced, line-level analog audio or for AES-3 digital audio, cross-connects on punch or other wiring blocks can be unshielded twisted-pair cable like the phone company uses. Using this type of cable helps keep punch block areas and walls neat and uncluttered. CAT5 cross-connect wire is also available. Not terminating shields increases the density of punch blocks, too. There is almost never any need to carry shields through punch blocks, and the user throws away ⅓ of the block's capacity trying. If using a shielded cable, remember to terminate only one end. I prefer to make a pigtail of all the shields and solder or crimp-connect it to a ground bus bar running near the blocks. Bring the permanent cables in behind the punch blocks, or permanent in one end and cross-connects out the other, so that permanent and cross-connected wiring is as separate as possible.

I have reluctantly decided that wiring channel, such as that made by Panduit, is a mixed blessing at best. Never mount a wire-trough channel upside down. As soon as you remove the cover, all the wires fall out. If you mount it sideways, put a wire-tie anchor inside it every so often, or anchor a Velcro wire-tie instead so the wires can be held up and to the back of the channel, out of the way of the cover. Another drawback is that the first time a cable has to be added in a hurry, the wiring channel covers tend to get removed and then not put back afterwards. Instead, use metal or plastic D-rings. Use the plastic ones that have a little seam that you can thread wires through without having to pass the end through each ring. They also have screw holes to anchor them down. Placing one about every foot and in corners will keep wires organized but not inaccessible — and there are no covers to lose. When appearance is paramount, like running wires that are in public view, opt for the wiring channel.

There is no such thing as too much documentation, a point that cannot be stressed heavily enough. Because I usually work with a crew of several people, I generate lots of documentation. In addition to the layout sheets I mentioned earlier, I generate a wiring and cross-connect list for each wiring block plus a wire running list for each room. That way I have created essentially a complete virtual studio on paper. Once this is done it's easy to go back and verify that the crew actually ran the wires as they were intended. It also serves to verify the documentation. It's easy to create documentation in a spreadsheet, database or forms program. I'm planning to document my next studio project in HTML, complete with hyperlinks for the cross-connects. The advantage is that it can be viewed on any browser and easily modified — with the right passwords.

Good old-fashioned written documentation is not yet obsolete, either. Take a big three-ring binder and use tab separators for each studio and sheet protectors for each page. Mark the revision date or number on each page, so it is obvious which version of a page is out of date. Generate and give the client multiple copies of the documentation and multiple copies of any digitally-stored documents too. Keep copies for yourself. Stations lose paperwork easily during ownership or engineering personnel changes.

Test, test and test again

Before a studio is finished, ring out every wire and every cross-connect, either with an ohmmeter or a cable tester. Test cables for continuity, shorts and polarity. Some wiring blocks will have trouble with AES cable, due to the larger insulation required to make the higher cable impedance, and the engineer may need to punch the occasional wire down twice or take other remedial action.

Jocks and production people can't use features they don't know exist, and who better to show them than the installer himself? Show the program director and the production director everything the studio will do. Make sure they are happy with how it works. This is often the last chance to ensure that the studio's users' needs have been met.

This is an exciting time to be building studios. While the pressures to keep costs down are great, and the flexibility and features desired of a modern studio are many, the tools for accomplishing these goals are plentiful. With proper planning and wiring techniques, the experienced installer can build first-class studios that will also pass the test of time without busting the budget.


Patton is president of Michael Patton and Associates, Baton Rouge, LA. Contact him through www.michaelpatton.com.




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